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24 April, 2019

The Ultimate WSPR Spot - part 2

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Being spotted by the designer of my WSPR transmitter must be the ultimate WSPR spot! Perhaps only surpassed by being spotted by the design...
12 April, 2018

Power regulator works as polarity protection

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Step-down converter based on LM2596. Note the damaged chip Ok, now I've done the test. My QRPLabs U3S runs off a 12 Volt power supp...
04 March, 2018

Deteriorating ceramic filters due to DC

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Tandberg Huldra 10 Tasos, SV8YM, has written about " The Mysterious Case of the Withering Filters ". This seems to affect not ...
1 comment:
27 December, 2017

QRSS experiments: FSKCW and Slow Hell

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These last few days I've been experimenting with my QRPLabs Ultimate 2 and Ultimate 3s transmitting on 7 MHz. In addition to WSPR, the ...
24 December, 2017

FT8 anomaly or long delayed echo?

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My friend Alf, LA2NTA, has sent me these screenshots from when he has been operating FT8. The first image is when operating 10 meters and to...
1 comment:
11 June, 2017

Simple interference fix for the Chinese Pixie

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The Chinese Pixie transceiver operating at 7023 kHz has become very popular. It often costs less than 5 USD on Ebay. Like most Pixies it is ...
23 February, 2017

Comparing two antennas with WSPR

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Ultimate 3S with 5-band relay module in front, variable LM2596 power supply (with voltmeter) for the power amplifier  behind left, a va...
27 November, 2016

Even better low-pass filters for transmitters

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The last issues of QEX have featured two interesting articles by Gary Cobb, G3TMG. He outlines the advantage of using Zolotarev designs for ...